The overall goal of the Neuroimaging core is first to achieve homogeneous acquisition of structural, perfusion, and diffusion tensor MRI at the three recruitment centers on 470 subjects, with two or more MRIs on 260 subjects. Second, to perform automated image processing of structural MRI including intensity normalization, segmentation of structural MRI, spatial normalization, and automated analysis of brain structure using Freesurfer software. The Core will: provide an overall cohesion to the collection of imaging data, create a data repository for program wide access to shared information, support program wide methodological development, and will ensure uniform methods of acquisition, so that data collected at the different sites can be pooled. 1) Establishing harmonized acquisition of structural MRI (T1 and FLAIR), diffusion tensor MRI, and arterial spin label perfusion MRI at all three acquisition sites (UC San Francisco, UC Davis, and U So Cal); 2) Performing all MRI scans at the Center for Imaging of Neurodegenerative Diseases, VA/UCSF 3) Establishing QA procedures and insuring continued quality control of MRI acquisition at all 3 sites; 4) Archiving and managing all MRI data acquired at all 3 sites; 5) Coordinating MRI readings by radiologists and maintaining quality control and rater reliability of clinical readings, and consistency in identifying lacunar infarctions and cortical strokes on MRI; 6) Performing intensity corrections (bias field corrections); 7) Image segmentation of structural MRI (GM, WM, CSF, white matter lesions (WMLs), using Expectation maximization likelihoold software. 8) Develop improved MRI segmentation techniques which provide more sensitive measures of changes in brain structure (e.g. loss of intensity of WM on T-1 weighted scans) 9) Spatial normalization of all data . 10) Performing Freesurfer analysis including quantification of cortical thickness measurements and parcelation of brain regions including total hipppcampal volume 11) Ensuring rater reliability and continue rater testing for all manual steps in the above- 12) Maintaining an image repository of raw and processed data and data base of all results. 13) Providing raw and processed image data to members of the PPG on a timely basis; 14) Providing raw and processed images and data to outside qualified investigators who request data, consistent with the data sharing plan.